APPLICANT'S ABSTRACT: An Outpatient Treatment Research Center is proposed that will specialize in the evaluation of outpatient services, including methadone maintenance and drug free modalities. The focus will be on secondary analysis of intake during treatment, and post-treatment follow-up records obtained as part of the DATOS family of studies. It will serve as one of two DATOS Field Research Centers responsible for conducting independent (but coordinated) studies that will address modality-specific issues (i.e., separately for outpatient and residential treatment settings) and achieve broad conceptual integration and application of findings. A DATOS Coordinating Center will continue followup data collection and related assessment studies as well as conduct cost-benefit evaluations with inputs from the Field Research Centers. This organizational plan will take advantage of special strengths of various research teams and ensure that together they conduct complementary, non-duplicative studies. Experience from previous large-scale and multisite treatment evaluations will guide the work conceptually, especially treatment process and outcome research based on the Drug Abuse Treatment for AIDS-Risk Reduction project (DATAR), a NIDA-funded treatment research demonstration grant for enhancing community- based outpatient programs. The analytical framework developed and implemented as part of DATAR studies on outpatient methadone treatment will be applied and elaborated with special attention devoted to the DATOS-Adult files. The incremental research plan to be applied across the 5-year project will focus on four sequential dimensions of outcome criteria: early treatment dropouts (<90 days), during-treatment performance, year 1 followup outcomes, and year 3 followup outcomes. During-treatment criteria will emphasize program engagement and compliance indicators, while followup criteria will emphasize drug use, HIV/AIDS risks, criminality, employment, and psychosocial adjustment measures. Major domains of predictor variables will include sociodemographics, drug use history, psychosocial background (psychopathology, cognitive deficits, work and social skills), treatment motivation (treatment history, readiness, legal pressures), support systems (family and friends), therapeutic engagement (length of stay, session attendance, indications of rapport between client and counselor), and program environment (staff structure, policies, procedures). General elements of this evaluation framework will apply to all DATOS-family databases. The major objectives include: (1) the description of treatment process and outcomes from typical programs, (2) identification of client, program, and service delivery factors related to treatment engagement and outcomes, and (3) development of statistical models that help clarify interrelationships among predictor and outcome measures. The results will lead to treatment improvement strategies for policy development.